DOS BULLETIN - Dansk Ortopædisk Selskab

2010-378_DOS nr. 3 2010 29/09/10 10:08 Side 130
Active immunization against Staphylococcus aureus (
ica+) periprosthetic osteomyelitis in rats
Janne Koch, Helle Krogh Johansen, Nina Vendel-Jensen,
Asger Lundorff Jensen, Steen Sejer Poulsen, Niels H. Søe
Faculty of Health Science, Department of Experimental Medicin;
Department of Clinical Microbiology, Rigshospitalet; Department of
Anesthesiology, Intensive Care and Operations, Gentofte Hospital;
Faculty of Life Science; Faculty of Health Science,
Biomedical Department; Hand Section Gentofte,
Department of Orthopaedic, Herlev Hospital
Background: Staphylococcus aureus may form biofilms on metallic and
polyethylene implants causing osteomyelitis infections difficult to eradicate
from bone, joints and surrounding tissues. The biofilm formation is
linked to the ica- gene and leads to significant resistance to antibiotics.
Purpose: We have searched for a synthetic PNAG oligosaccharide conjugate
vaccines to prevent osteomyelitis around implants in a rat kneeimplant
model.
Methods: Fourteen Sprague-Dawley rats were operated with a non-constrained
knee prostheses and divided into a vaccine group ( N=6) and a
control group ( N=8) . The two groups received a bacterial inoculums of
103 S.aureus, ica+, MN8 in the tibia and the femur marrow before insertion
of the prosthesis. The vaccine group received active immunization
with a synthetic oligosaccharide 9G1cNH2 conjugated to tetanus toxoid
given 3w, 2w and 1 w before implantation of the prostheses. After two
weeks , the animals were sacrificed and all the specimens were prepared
for analysis. Blood analysis and radiological findings were collected.
Findings: The vaccine group showed a significant effect in all four
parameters as shown by the clinical data. G/n Microb 1AG X-ray Path.
V/6 1.6 273 2.5 4.0 C/8 2.3 383 5.3 8.1
Conclusion: The animal model is suitable to reliably induce implant
osteomyelitis and demonstrated that active immunization ( vaccination)
can significant reduce the consequences of infection from an ica+ bacterial
osteomyelitis. In the vaccine group, with the biofilm producing
bacteria, a trend towards an effect is seen.
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